Abstract
OBJECTIVES: Computed tomography (CT), the reference standard for diagnosis of intraabdominal injury (IAI), carries risk including ionizing radiation. CT-sparing clinical decision rules for children have relied heavily on physical examination, but they did not include focused assessment with sonography for trauma (FAST), which has emerged into widespread use during the past decade. We sought to determine the independent associations of physical examination, laboratory studies, and FAST with identification of IAI in children and to compare the test characteristics of these diagnostic variables. We hypothesized that FAST may add incremental utility to a physical examination alone to more accurately identify children who could forgo CT scan. METHODS: We reviewed a large trauma database of all children with blunt torso trauma presenting to a freestanding pediatric emergency department during a 20-month period. We used logistic regression to evaluate the association of FAST, physical examination, and selected laboratory data with IAI in children, and we compared the test characteristics of these variables. RESULTS: Among 354 children, 50 (14%) had IAI. Positive FAST (odds ratio [OR] = 14.8, 95% confidence interval [CI] = 7.5 to 30.8) and positive physical examination (OR = 15.2, 95% CI = 7.7 to 31.7) were identified as independent predictors for IAI. Physical examination and FAST each had sensitivities of 74% (95% CI = 60% to 85%). Combining FAST and physical examination as FAST-enhanced physical examination (exFAST) improved sensitivity and negative predictive value (NPV) over either test alone (sensitivity = 88%, 95% CI = 76% to 96%) and NPV of 97.3% (95% CI = 94.5% to 98.7%). CONCLUSIONS: In children, FAST and physical examinations each predicted the identification of IAI. However, the combination of the two (exFAST) had greater sensitivity and NPV than either physical examination or FAST alone. This supports the use of exFAST in refining clinical predication rules in children with blunt torso trauma.